Different network operators within almost every country around the world deploy common carrier mobile communication systems. Many of these network operators, form roaming partnerships to offer international roaming to their subscribers traveling abroad, and to travelers visiting their territory and using their foreign mobile phones. Some of the home network operators often have preferred bilateral roaming agreements with some visited network operators. The preference is based on either more favorable wholesale roaming charges (or discounts) or more profits for the home network operator than that of non-preferred network operators. Therefore, “preferred” networks are those networks that the home network operator prefers its outbound roamers to register with when traveling outside their home coverage area. Non-preferred networks are also termed as “non-benefiting” networks.
Network operators can maximize their margins and the roamers can get more attractive roaming rates and services, if the roamers roam in the home network operator's preferred networks. When the roamers roam into a zone outside their home network's (i.e. an HPMN) coverage area, they may attempt to register with one or more visited networks (i.e. VPMNs), one at a time, based on various criteria. One or more of these VPMNs may also include the “non-preferred” VPMNs. Hence, protecting the existing roaming revenues and growing them further has become an important priority for various network operators worldwide.
However, current methods of controlling which network the subscriber registers with when he/she is roaming have certain limitations. For example, a commonly used approach includes storing a list of preferred networks on a SIM in the subscriber's handset. However, this list often get outdated as many of the home network operators may tie up roaming agreements with several other visited network operators after the SIM has already been sold to subscribers or SIM vendors. Although, there are techniques to update this SIM list using Over-The Air (OTA) approach, however, the OTA update requires OTA support by the SIMs and in many cases the SIMs do not have such support. Also, the SIM list approach is not quick enough to adapt to the dynamic and distributed nature of preferred relationships between the HPMN operator and the VPMN operators in different countries.
Another approach, as taught by the inventor of U.S. application Ser. No. 7,072,651, filed on Aug. 5, 2003, describes a method and system for redirecting wireless network traffic and voice and data traffic under control of a network operator when a subscriber is roaming. This previous filing presented an innovative solution in a GSM network environment for redirecting an outbound subscriber's traffic (i.e. Traffic Redirection) to a preferred network, based on some distribution control. This solution is based on MAP signaling and is deployed at operator's HPMN that provides a SIM independent solution. It also known that the TR solution can be combined with the OTA approach in order to achieve better results of redirecting the subscriber's traffic to the preferred network.
In this previous TR filing, the solution for Traffic Redirection (TR) or Steering of Roaming (SoR) was presented in two approaches: an in-signaling based approach (also referred to as active mode) and a passive monitoring based approach (also referred to as passive mode). All location update attempts by the subscriber in a VPMN are received at a Visitor Location Register (VLR) in the VPMN. The VLR then sends a MAP Location Update (LUP) message to a Home Location Register (HLR) in the subscriber's HPMN. In the active mode, these LUP messages are redirected through the HPMN deployed TR solution, which decides whether to send a reject error message to the VLR, or simply redirect the LUP message to the HLR. In an alternate technique, based on the passive mode, the HPMN deployed TR solution monitors the LUP message by tapping on a signaling link (e.g., roaming SS7 link), from the VLR of the VPMN to the HLR of the HPMN, and thereby decides whether to send a reject error message to the VLR of the VPMN.
Since the previous TR filing, Global System for Mobile communication Association (GSMA) introduced IR.73 SoR Implementation Guidelines for implementing traffic redirection. The purpose of the guideline, with respect to the previous TR filing, is to reduce the impact of the HPMN deployed TR solution on the “non-preferred” VPMNs (i.e. the rejected VPMNs) that may be rejected due to some distribution control. Moreover, the IR.73 guideline applies to both: active mode and passive mode. Hence, both approaches are required to follow the IR.73 guideline, which teaches that the HPMN should do its best not to send any further messages, after a location update acknowledgement message (i.e. LUP-ACK message) has already been sent to the VPMN, using same transaction id. In other words, during a location update process using a particular transaction id, the HPMN should not send any message after sending the LUP-ACK message, which according to the GSM standards is the final message in the location update process.
The active mode of the previous TR filing clearly followed the IR.73 guideline by not sending any MAP/TCAP messages after LUP-ACK message. However, the passive mode approach of the previous TR filing may not conform to the IR.73 guideline when the HPMN's HLR sends a MAP ISD message or a MAP LUP-ACK message to the VPMN VLR, after the HPMN has already sent a reject error message in the LUP-ACK message to the VPMN VLR, using the same transaction ID. In addition, in passive mode of the previous TR filing, only System Failure (SF), Unexpected Data Value (UDV), Missing Data (MD), and TCAP/MAP abort were considered as an error codes. Moreover, the passive mode of the previous TR filing, did not handle error codes like Roaming Restricted Due to Unsupported Feature (RRDuF) and Roaming Not Allowed (RNA).
In accordance with the foregoing, there is a need in the art of a system, method, and a computer product, which provides a passive mode TR solution that is compliant with GSMA IR.73 guidelines, and is able to handle additional error codes like RRDuF and RNA to restrict the subscriber from registering with non-preferred networks.